Warning device for cooling water system for transformers



July 19, 1955 H. H. KROKSTRAND 2,713,678

WARNING DEVICE FOR COOLING WATER SYSTEM FOR TRANSFORMERS Filed June 15, 1949 United States Patent 0 WARNWG DEVICE FOR COOLING SYSTEM FOR TRANSFORMERS Hans Heitmand Krokstrand, Oslo, Norway, assignor to Christiania Spigewerk, Oslo, Norway WATER With water-cooled transformers it is necessary to provide for a warning in case the cooling-water system should cease functioning for instance as a result of a stopping up of the supply of water or the stopping of the motor, which is dn'ving the circulating pump. When the cooling-Water system stops functioning the transformer has to be put out of action, because it would otherwise be burned out.

The ordinary warning devices known up to now are all based on the use of a moveable member, for instance in the shape of a flap or a vane arranged in a part, through which the cooling-water is streaming, and which is kept in one position by the streaming cooling- Water, but which by gravity or from other influence is moved to another position, if the cooling-Water stops streaming. By this movement of said member an electric circuit, which is executed in such a way that a warning is given, is closed or broken.

However, experience has shown, that such warning devices are not reliable. This is due to the fact that mud is gradually deposited on said movable member or on the surrounding walls, with the result, that the member sticks and does not move, when the stream of cooling-water stops. This inconvenience is particularly prevalent when river-water is being used as coolingwater.

The object of the present invention is to provide for a warning device, which does not suffer from this inconvenience and which at the same time involves other advantages compared with known arrangements. What mainly distinguishes the invention from previously known Warning devices consists in the fact, that according to the invention no movable parts are used. The warning device according to the invention consists in an electric circuit carried out in such a way, that the current will have to pass through the water in a compartment, where the water-level is dependent upon the working of the cooling-water arrangement, and an electrode, of which one end is located in this compartment and arranged in such a way, that the electrode will be in contact with the water or not depending upon the waterlevel.

As will be easily understood a warning device based upon this principle can be carried out in several different ways. Said compartment into which the electrode has to extend can for instance be connected with the cooling-water arrangement in such a way, that the waterlevel-for instance by means of an ejector-efiectis at its lowest, when the cooling-water arrangement is functioning and rises, when the cooling-water stops streaming. In this case the electrode can be arranged in such a way, that the circuit is closed if the cooling arrangement stops functioning.

However, the warning device according to the invention is preferably carried out in such a way, that said circuit normally is closed and is broken, if the coolingwater arrangement stops functioning. In this case the electrode can for instance extend into a part of the conduit of cooling-water which is located in such a way, that it will be drained off, if the supply of cooling-water stops. Said compartment, into which the electrode has to extend, is however preferably constituted by a separate container, from which the electrode easily can be Withdrawn for inspection and cleaning, and which container itself also easly can be cleaned without interrupting the stream of cooling-water. Said circuit is conveniently constituted by a relay-circuit, the relay of which closes a signal circuit, if the relay-circuit is broken. The relay-circuit is conveniently driven by alternating current to avoid electrolysis on the electrode.

If the device according to the invention is carried out in such a way as described above, where the circuit normally is closed, the advantage is obtained, that a signal will be given not only, if the cooling arrangement stops functioning, but also if mud is deposited on the electrode, so that this is no longer conducting, 'or if the circuit or the supply of current to the circuit is broken.

The invention will in the following be described more in detail in connection with the drawing, which diagrammatically illustrates a convenient embodiment of the invention. In the drawing 1 indicates the conduit of cooling-water coming from the transformer. This conduit discharges into a container 2 open at the top, which container at one of its ends is provided with an outlet 3. Between this outlet and the conduit of cooling-water is located a partition-wall 4, which close to the bottom is provided with one or several openings 5. The flow-section of this or these openings has a dimension which is smaller than that needed for the passage of the total quantity of cooling-water, which by normal working of the cooling-water arrangement is supplied to the container from the conduit 1. The partitionwall 4 does not extend all the way up to the upper edge of the container 2, so that the water at 6 can flow over the edge of the partition-wall 4. In this way the level of the water in the container 2 to the right of the partition-wall 4, when the cooling-water arrangement is working normally, will be about level with the upper edge of the wall 4, but will fall owing to the streaming out of the water through the opening 5, if the supply of cooling-water is interrupted or much reduced.

7 is an electrode, which extends down into the container 2, so that its lower end is located between the opening 5 and the overflow 6. Between the electrode 7 and the supply-conduit 1 is arranged a partition-wall 8, which extends from the top and downwards so far, that an opening will be left at the underside of the partition-wall. This partition-wall serves the purpose of making the surface of the water around the electrode 7 calmer.

As will appear from the drawing, the electrode is coupled in a circuit, which contains the secondary winding 10 of a transformer 9, the primary winding 11 of which over fuses 12 is supplied with current for instance from the lighting-circuit. The lower part 13 of the transformer is assembled with a relay with armature 14 and contacts 15. These contacts are located in a signalcircuit 16.

The operation of the device is the following:

When the cooling-water arrangement is functioning the container 2 will, to the right of the partition-wall 4, be filled with water to a level somewhat above the overflow 6. The electrode 7 will consequently be in contact with the water, and the relay-circuit is closed. The armature 14 will therefore be kept in a lifted position and the signal-circuit is broken.

If now the supply of cooling-water is stopped, the water in the container 2 will drain 0H, and the relaycircuit will break. The armature 14 drops, and the signalcircuit is closed, and a signal is given.

The same will occur, if the electrode should be with mud, so that it is no longer conducting, relay-circuit is broken from other reasons, or supply of current to the transformer is broken.

Compared with previously known warning-devices with movable members of impulse enclosed in a part through which the cooling-water is streaming, the present invention besides greater working reliability also has the advantage, that the electrode 7 as well as the container 2 can be inspected and cleaned without interrupting the cooling-water.

I claim:

In a system of circulating liquid the combination of a container, a partition wall dividing the container into two vertical chambers, into one of which the circulating liquid is continuously supplied, a discharge opening at the bottom of the other chamber, said partition wall being at its lower end provided with an opening of such small dimensions that the total amount of liquid which under normal conditions of the system is supplied to the container cannot pass coated if the if the through the opening, the excess of liquid flowing through an overflow in the partition wall at a higher level than said opening, a second partition extending downwardly part way into said chamber to which the liquid is supplied to form a relatively quiet compartment and means for giving an indication of when the liquid falls below a certain fixed point located in said compartment.

References Cited in the tile of this patent UNITED STATES PATENTS 859,816 Kelsch July 9, 1907 1,561,813 Williams Nov. 17, 1925 1,978,392 Von Brockdorif Oct. 23, 1934 2,248,665 Fischer July 8, 1941 2,261,495 Ewertz Nov. 4, 1941 2,368,471 Horan Jan. 30, 1945 2,382,516 Sprague Aug. 14, 1945 I FOREIGN PATENTS 350,277 France Oct. 30, 1905 

